* {
  margin: 0;
  padding: 0;
  border: none;
}

.box {
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  align-items: center;
  width: 800px;
  height: 500px;
  margin: auto;
  background-color: skyblue;
}

.box > p {
  color: #fff;
  font-size: 2rem;
  text-align: center;
  line-height: 200px;
}

.box > button {
  width: 150px;
  height: 70px;
  color: beige;
  font-size: 1.5rem;
  border-radius: 10%;
  text-align: center;
  background-color: #ccc;
}

.active-btn {
  background-color: orangered !important;
  color: whitesmoke !important;
}

.disable {
  background-color: #ccc !important;
  color: whitesmoke !important;
  cursor: not-allowed;
}

div > span {
  font-size: 20px;
  color: wheat;
  text-indent: 10px;
}

/* 作业打印格式 */
pre {
  margin-top: 300px;
}
